Distributed Energy, Nov/Dec 2016, by Daniel P. Duffy.
http://foresternetwork.com/distributed-energy-magazine/be-energy/fuel-cells/a-fuel-phase-transition/

"There is a quiet (and sometimes not so quiet) revolution taking place in the way America powers its motors, engines, and turbines. Industrial motors, traditionally powered by diesel and gasoline fuels, are transitioning to a new fuel source—natural gas."